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Yee Huang, Li Nan, Chenwen Xiao, Jie Dong, Ke Li, Jvfen Cheng, Quanan Ji, Qiang Wei, Guolian Bao, Yan Liu Institute of Animal Husbandry and Veterinary Medicine, Zhejiang Academy of Agricultural Science, Hangzhou, 310021, People’s Republic of ChinaCorrespondence: Guolian Bao; Yan Liu, Institute of Animal Husbandry and Veterinary Medicine, Zhejiang Academy of Agricultural Science, Hangzhou, 310021, People’s Republic of China, Email baoguolian@163.com; 35792191@qq.comPurpose: Outer membrane vesicles (OMVs) are spherical nano-sized proteolipids secreted by numerous pathogenic Gram-negative bacteria. Due to the immunostimulatory properties and protective efficacy, OMVs have received increasing attention as a candidate for the vaccine to prevent and treat bacterial infections. However, the immune response remains elusive due to the low structural stability and poor size homogeneity of the vesicles. In this study, OMVs were used to coat self-assembled glycyrrhizic acid nanoparticles (GANs) and obtain a stable OMV vaccine. The immunoprotective effects and anti-infection efficacy were evaluated in vivo and in vitro.Methods: The OMVs were prepared by ultrafiltration method and fused with GAN through mechanical extrusion. The characteristics, including morphology, hydrodynamic size, zeta potential, and stability were evaluated. The in vitro immunological function of GAN-OMV on the macrophages and in vivo immune efficacy and anti-infection effect were examined and compared.Results: The results showed that the GAN-OMV were homogenous with a size of 130 nm and a stable core-shell structure. Micropinocytosis-dependent and clathrin-mediated endocytotic pathways effectively internalized the GAN-OMV into the macrophages and promoted cell proliferation, cytokine secretion, and M1 polarization. Furthermore, subcutaneous GAN-OMV vaccination contributed to significantly higher Borderella bronchiseptica (Bb)-specific antibody production and lymphocyte proliferation. The splenic lympho

Yee Huang,1 Li Nan,1,2 Chenwen Xiao,1 Quanan Ji,1 Ke Li,1 Qiang Wei,1 Yan Liu,1 Guolian Bao1 1Institute of Animal Husbandry and Veterinary Medicine, Zhejiang Academy of Agricultural Science, Hangzhou 310021, People’s Republic of China; 2Zhejiang Normal University, Jinhua 321000, People’s Republic of ChinaCorrespondence: Yan Liu; Guolian BaoInstitute of Animal Husbandry and Veterinary Medicine, Zhejiang Academy of Agricultural Science, Hangzhou 310021, People’s Republic of ChinaEmail 35792191@qq.com; baoguolian@163.comBackground: Rehmannia glutinosa polysaccharide is the main reason that contributes to the immunological function of R. glutinosa. Due to its disadvantages in clinical use, here we designed the PEGylation nano-RGP (pRL) to improve the drug-targeting effect and the immunological function. Our present work aims to establish the optimum condition of preparing the pRL and to investigate its immunological function on macrophages.Methods: pRL was prepared by thin film hydration method combined with ultra-sonication technique. And its preparation conditions were optimized with response surface methodology. Also, the lyophilization method was optimized. The characteristics of the pRL were evaluated, including particle size, drug loading, encapsulation efficiency and morphology. The immunological function of pRL on macrophage was investigated through CCK-8 test, ELISA and flow cytometry.Results: The lipid-to-cholesterol molar ratio of 8:1, the addition of DSPE-PEG2000 of 9% and the lipid-to-drug ratio of 5.4:1 were the optimum preparation technology for pRL. The encapsulation efficiency (EE) of pRL under this preparation technology was 95.81±1.58%, with a particle size of 31.98 ± 2.6 nm. The lactose-to-lipid ratio (2:1) was the optimal lyophilization method. pRL promoted macrophage proliferation, which is significantly better than that of nano-RGP without PEGylation (RL). pRL-stimulated RAW264.7 cells showed a h

Yee Huang,1 Tao Qin,2 Yifan Huang,2 Zhenguang Liu,1 Ruonan Bo,1 Yuanliang Hu,1 Jiaguo Liu,1 Yi Wu,1 Deyun Wang1,2 1College of Veterinary Medicine, Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 2College of Animal Science and Veterinary Medicine, Fujian Agriculture and Forestry University, Fuzhou, People’s Republic of China Abstract: Nanomedicine, the medical application of nanotechnology, promises a seemingly limitless range of applications from drug delivery to adjuvants and therapeutics. Our current research is focused on natural polymer-based liposome adjuvants. With the aim of inducing protective and long-lasting immunity, the immunological adjuvant activity of Rehmannia glutinosa polysaccharide liposome (RGPL) was investigated. In vivo, the splenic lymphocyte proliferation ratios and ovalbumin-specific immunoglobulin G titers of ovalbumin-RGPL-vaccinated mice were significantly upregulated. In draining lymph nodes, the expression of MHC II+CD11c+ and CD86+CD11c+ was increased by RGPL; in addition, the percentages of central memory cells (TCM) and effector memory cells (TEM) were also elevated. RGPL could effectively provide adequate antigen exposure in lymph nodes. In vitro, RGPL could promote dendritic cell maturation and enhance dendritic cell functions, such as the mixed lymphocyte reaction and antigen presentation. Overall, the results demonstrated that RGPL has the potential to act as an effective controlled release vaccine adjuvant. Keywords: Rehmannia glutinosa polysaccharide liposome, adjuvant, controlled release, ovalbumin, dendritic cells

Zhenguang Liu, Li Luo, Sisi Zheng, Yale Niu, Ruonan Bo, Yee Huang, Jie Xing, Zhihua Li, Deyun Wang Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, People’s Republic of China Abstract: Cubosomes have been explored as drug and antigen carriers in the past few years. A few reports have described that cubosomes can enhance the ability of immunostimulants to generate strong immune responses. Polysaccharide (PS), an immunostimulant, has been reported to be a promising adjuvant for vaccines. Herein, we incorporated PS into cubosomes to generate PS–cubosome (Cub-PS) nanoparticles, and Cub-PS was characterized by small-angle X-ray scattering scattering and cryo-field emission scanning electron microscopy. The immunological activity of Cub-PS was compared with that of Cub and PS. The results demonstrated that Cub-PS elicited more potent immune responses than Cub or PS alone. The enhanced immune responses might be attributed to the promotion of antigen transport into draining lymph nodes and efficient dendritic cell activation and memory T-helper cell differentiation in draining lymph nodes. Overall, these findings indicate that cubosomes have the potential to enhance the ability of immunostimulants to generate an immune response. Keywords: cubosomes, polysaccharides, cryo-FESEM, lymph nodes, dendritic cells, memory T-helper cells